The invention relates to a display device, in particular for a vehicle, the display device having a pointer which can be actuated by a measuring mechanism, and for the analog representation of measured values, fixed scale marks are assigned to the pointer. A display is arranged in a region over at least part of which the pointer travels. For representing variable information, it is possible to represent scale labeling on the display.
Such display devices are known and are used in the form of analog pointer instruments in measuring equipment, for example. In the known devices, scale labeling which is located on the scale plate can be generated and changed by electronic actuation. In such cases, the location of the scale labeling is permanently predefined in relation to the scale marks.
Other known display devices having an analog pointer instrument and a display, over which the pointer travels, for representing variable information have a large scale area which can be actuated, in which context all the display elements including the scale marks can be actuated in a variable fashion and represented on the display. However, the size of the display area which can be actuated is a direct measure of the manufacturing costs of the display, and thus of the display instrument, make these known display instruments very costly. Furthermore, the representation on the display is defined as a planar display, something which restricts the optical configuration possibilities of this display device in terms of both ergonomic and aesthetic criteria.
In order to remedy this, the object of the present invention is to design a display device in such a way that it provides an analog representation of measured values with a flexible representation of information on the scale area, accompanied by low manufacturing costs for the display device.
The object is achieved with a display device of the type mentioned above by virtue of the fact that the scale marks are arranged outside a display region which can be actuated and that at least part of the display extends along the scale marks and the scale labeling can be represented in this region. A display device according to the invention thus makes it possible, without having to dispense with an extensive representation of information, to keep the display region which can be actuated small. A display device according to the invention can therefore be manufactured in a particularly cost-effective way. In addition, in a device according to the invention the scale marks are designed independently of the display, making it possible, for example, to make it easier to perceive by a viewer and/or enabling it to be matched in terms of design to the surrounding instrumentation (for example the dashboard of an motor vehicle).
According to one advantageous development of the invention, the scale labeling can be varied, enabling both the display region of the measuring instrument and the unit which is being displayed to be varied very easily without the instrument having to be adapted mechanically. This is significant, for example, in the case of the speedometers of motor vehicles if they are to be marketed throughout the world. The displayed unit can then be converted from, for example, kilometers per hour to miles per hour by simply changing the actuation of the display and of the pointer measuring mechanism. It is particularly easy if this change is carried out by actuation software.
For a flexible representation of information in a way which is dependent only on the respective actuation, it is of particular advantage if the display is a dot-matrix display. With such display it is possible to display any number of representations which are each composed of a quantity of actuated dots of a dot-matrix.
It is advantageous that the display is particularly inexpensive and can be manufactured in large series if it has a liquid crystal cell. Liquid crystal cells provide the additional advantage that, owing to their low power consumption, they do not heat up during operation and thus do not contribute to an undesired heating of the display instrument.
According to another advantageous development of the invention, the pointer can be pivoted about an axis which is approximately perpendicular to the representational plane of the display. Such round instruments are particularly easy to read and require only a small installation area.
The display device can advantageously be of very compact design if the pointer has, in a region which is turned away from a pointer tip, a pointer hub which is connected to a pointer shaft, and if the axes of rotation of the pointer shaft and of an output shaft of the measuring mechanism are arranged so as to be congruent or approximately parallel to one another. Preferably, the pointer shaft and the measuring mechanism output shaft are connected to one another so as to form a single component. As a result, owing to a reduction in the number of individual components, the number of mounting processes during the fabrication of the display device is reduced and the inventory holding of the required individual parts is simplified.
According to another advantageous development of the invention, a gear mechanism which transmits a rotary movement of the measuring mechanism output shaft to the pointer shaft is arranged between the measuring mechanism output shaft and the pointer shaft. This makes it possible to separate the measuring mechanism from the pointer spatially and to select a flexible arrangement of the measuring mechanism such that the installation space which is available in the display device is used to an optimum degree. Preferably, the gear mechanism is a flexible drive mechanism, friction wheel mechanism or gearwheel mechanism, so that the rotary movements are transmitted in a simple and reliable way with only a few movable components. The installation space which is available at the rear of a display and/or of a dial of a display device is very limited owing to the large number of electronic and mechanical components to be accommodated so that it is of great advantage if at least part of the gear mechanism is arranged in front of the side of the representational plane of the display which faces a viewer. In order to avoid disrupting the structural impression of the display device and in order to protect the gear mechanism against dirt, the parts of the gear mechanism which are arranged in front of the representational plane are preferably covered on the viewer side with a panel.
If large areas of information, such as, for example, traffic guidance information, is represented on the display of the display device according to the invention, during which the pointer is not required, it is advantageous if the pointer can be covered on the viewer side with a panel. This makes the display panel clearly visible without superfluous, distracting elements, as a result of which the attention of a viewer is directed completely at the represented information. Preferably, the panel which covers a gear mechanism is identical to the panel with which the pointer is covered.
The legibility of measured values which are represented with the pointer is particularly good if the scale marks are arranged in the direct vicinity of, or within, a region of the display device over which the tip of the pointer travels. Here, it is particularly easy if the scale marks are located on the display. The ergonomic and design possibilities which are provided by the display device according to the invention can, however, be particularly well exploited if, according to one advantageous development of the invention, the scale marks are located on a frame element, and the frame element engages at least partially around the display. Here, the display is preferably inserted into a recess of the frame element, as a result of which the frame may simultaneously be a holder of the display.
Especially because of the possibility of easier fabrication, displays usually have a rectangular shape. In order to be able to give the frame element a shape other than a rectangular shape, for example a round or elliptical shape, it is of particular advantage if the frame element is fitted onto the display. As a result, edge regions of the display which are possibly not used do not need to be available as a display area which can be actuatedxe2x80x94because they are coveredxe2x80x94and can therefore be implemented easily and cost-effectively as untreated carrier surface.
It would be conceivable to illuminate the display device according to the invention by means of uplight, in particular, in order to make it legible in surrounding darkness. However, the legibility is particularly good if, according to one advantageous development of the invention, the frame element is a light guide. As a result, it is possible both to illuminate directly the scale marks which are provided on the frame element and to illuminate the display by means of light which may have been possibly extracted from the frame element in a selective fashion. The legibility and the visual impression of the display device is further improved if the scale marks are elevated or countersunk with respect to the representational plane of the display. In this way a plastic structure can be achieved.
In particular, when there is surrounding darkness, it is advantageous if the scale marks can be illuminated so that one can be sure of perceiving the represented information reliably even in darkness.
It would be conceivable to use the entire display region for representing information. However, it is frequently sufficient to use only parts of the display region. In this case, it is advantageous if part of the display is covered by a panel and a uniform structure of the display device is thus possible in this way.
It is conceivable, depending on the case, to represent only specific information on the display, for example, alternative scale labeling or warning information. However, it is of particular advantage if the display can be actuated freely in at least one part, as a result of which information can be represented flexibly on the display and even images, such as for example excerpts from maps of a traffic guidance system or video sequences, can be displayed.
The display is advantageously of simplified design if it has a region which cannot be actuated. This region which cannot be actuated is, for example, a region which is covered by a panel.
In order to safeguard an emergency operating function of the display device, for example in the case of a fault in the electronic system of a vehicle, it is advantageous if the display can be read without illumination. If a liquid crystal cell is used, said cell is therefore preferably transflective or reflective. It is of particular advantage if the display can be illuminated so that even when there is surrounding darkness the information represented on the display can be perceived.
According to another advantageous development of the invention, the display device has a dial, the scale marks being represented on the dial, and at least one region of the display which can be actuated being arranged in a recess of the dial. Such a design is suitable particularly if the display device is a component of a combination instrument, for example of a motor vehicle.